A COMPARISON OF CONDITIONAL AND DISJUNCTIVE INFERENCES - A CASE-STUDYOF THE MENTAL MODEL-THEORY OF REASONING

The mental model theory of reasoning postulates that individuals reaso n by constructing models of the situations described by premises, but the number of explicit models and the information in them is kept to a minimum. Among the novel predictions made by the theory are the follo wing three: 1. reasoning with conditionals should be easier than reaso ning with exclusive disjunctions; 2. reasoning with a minor premise th at affirms a constituent of a major premise should be easier than reas oning with a minor premise that negates a constituent of a major premi se; and 3. these two variables should interact, because reasoning with a premise that negates a constituent of a conditional calls for the c onditional to be fleshed out to two or three explicit models. The pres ent paper reports an experiment that corroborates all three prediction s.